The Nile has always been the source of all life in Egypt. Its fertilizing, life supporting inundation has been an object of worship since predynastic times. Although sources for offerings and related feasts are not known before the New Kingdom, they become more numerous during the Greek and Roman Periods. Evidence for this worship can be pursued until modern times, before the building of the High Dam made offerings in regard to a good flood unnecessary. Despite the importance of the inundation for Egypt, it is striking, that the God Hapi only played an inferior role in the Egyptian Pantheon and actually represents no more than a Genius. Not him, but other gods have the power to evoke the coming of the flood, while Hapi only incorporates it. In the Roman Period the god Nile/Hapi became more and more important - a fact that must be ascribed to the increasing worship of the god Serapis, newly created under Ptolemaios I., but also that of Osiris and Isis in the entire Mediterranean world.